An asteroid just under 11 yards in diameter will give the earth a very close fly-by tomorrow.
Listed as a PHA – Potentially Hazardous Asteroid by NASA, the space rock, 2017BX was discovered earlier this month and will pass at .7 of the distance between the earth and the moon. That’s a mere whisker in astronomical terms. (One lunar distance is 238855.708 miles.)
There is no indication that it will collide with the earth but we know from the Chelyabinsk meteor that exploded above the earth over Russia in 2013, that even smaller objects that don’t impact can cause major problems.
New PHA’s are being discovered all the time. The list on spaceweather.com of those so far discovered covers up to March 2, 2017.
A recent article from the Potsdam Institute for Climate Impact Research (PIK) points out that the asteroid impact that is attributed to killing off the dinosaurs wasn’t such a straightforward issue as first thought.
“The big chill following the impact of the asteroid that formed the Chicxulub crater in Mexico is a turning point in Earth history,” says Julia Brugger from the Potsdam Institute for Climate Impact Research (PIK), lead author of the study to be published in the Geophysical Research Letters. “We can now contribute new insights for understanding the much debated ultimate cause for the demise of the dinosaurs at the end of the Cretaceous era.” To investigate the phenomenon, the scientists for the first time used a specific kind of computer simulation normally applied in different contexts, a climate model coupling atmosphere, ocean and sea ice. They build on research showing that sulfur- bearing gases that evaporated from the violent asteroid impact on our planet’s surface were the main factor for blocking the sunlight and cooling down Earth.
In the tropics, annual mean temperature fell from 27 to 5 degrees Celsius
“It became cold, I mean, really cold,” says Brugger. Global annual mean surface air temperature dropped by at least 26 degrees Celsius. The dinosaurs were used to living in a lush climate. After the asteroid’s impact, the annual average temperature was below freezing point for about 3 years. Evidently, the ice caps expanded. Even in the tropics, annual mean temperatures went from 27 degrees to mere 5 degrees. “The long-term cooling caused by the sulfate aerosols was much more important for the mass extinction than the dust that stays in the atmosphere for only a relatively short time. It was also more important than local events like the extreme heat close to the impact, wildfires or tsunamis,” says co-author Georg Feulner who leads the research team at PIK. It took the climate about 30 years to recover, the scientists found. (source)
There is, somewhere in the vastness of space, a very large rock that is on a collision course with earth. Impacts have happened numerous times in the past and they will happen again unless the best minds on the planet find a way to divert or destroy the threat. Unlike the folks in the movie Armageddon, we haven’t reached that point in our technology yet.
A strike from a major asteroid is something that at this point in time simply cannot be avoided. If such a rock was discovered to be on a collision course today the best that we could hope for is that it landed in the ocean as the Chicxulub asteroid did.
Then “all” we would have to contend with is 30 years of cold and famine.